1. Field of the Invention
The present invention relates generally to a multiple assembly of optical curve molds formed in a single solid piece of polymer, and more particularly pertains to a multiple assembly of frontcurve molds formed in a single solid piece of polymer in which the assembly of frontcurve molds is used in a subsequent production process for molding cast ophthalmic lenses in mold assemblies, each comprising a frontcurve and a spaced basecurve, and wherein a molded lens such as a contact lens is formed therebetween.
2. Discussion of the Prior Art
As the ophthalmic lens industry has grown, and in particular the industry related to supplying contact lenses which are provided for periodic frequent replacement, the number of contact lenses required to be produced has increased dramatically. This has spurred manufacturers to strive for automated methods and apparatus which are adaptable to automated practices and consistent performance.
It is generally known in the prior art to make ophthalmic lenses, such as soft hydrogel contact lenses, by molding a monomer or monomer mixture in a mold such as one made from polystyrene or polypropylene.
Examples of this prior art can be found in U.S. Pat. Nos. 5,039,459, 4,889,664 and 4,565,348. These patents discuss therein the requirement for a polystyrene mold in which the materials, chemistry and processes are controlled such that the mold portions do not require undue force to separate by sticking to the lens or to each other. In contrast to the above polystyrene molds, another example is the use of polypropylene or polyethylene molds as described in U.S. Pat. No. 4,121,896.
The mold assembly to mold an ophthalmic contact lens typically includes a lower concave mold portion referred to as a frontcurve and an upper convex mold portion referred to as a basecurve. The concave surface of the lower frontcurve and the convex surface of the upper basecurve define therebetween a mold cavity for a contact lens.